Note: This cheat sheet page is still very much a work in progress. I’m not even half way through yet and my documentation is pretty sparse. I’ll add onto when I can and try making it more verbose.

Operators and Miscellaneous Stuff

Standard input

>

Standard output

<

End of file

<ctrl-d>

CAT

The cat command performs basic file manipulation.

File creation

cat > foo.bar
Entering a line of text
Entering another line of text
<ctrl-d>

File appending

cat >> foo.barEntering a new line of text

<ctrl-d>

File Displaying

cat foo.bar

File Displaying with counted lines

cat -n foo.bar

NL

The nl command is useful in reading lines.

Readline

nl foo.bar

Readline with regex

nl -b p^[E] foo.bar

Customizing readline deliminator

nl -s: foo.bar

WC

WC is a basic counting command

Counting lines, words separated by whitespace, and total characters

wc foo.bar

Counting only lines

wc -l foo.bar

Counting only words separated by whitespace

wc -w foo.bar

Counting only characters

wc -c foo.bar

GREP

Grep is a basic command for searching a file

Searching a single file

grep Enter foo.bar

Searching multiply files

grep Enter foo.bar text.txt

Counting found matches

grep -c Enter foo.bar

Hiding file name output

grep -h Enter foo.bar

Displaying own matched file names

grep -l Enter foo.bar

Ignoring case search

grep -i enter foo.bar

Including line numbers

grep -n Enter foo.bar

Inverted searching

grep -v Unix foo.bar

Word matching

grep -w Enter foo.bar

Streams And Pipes

Stream File Descriptors

stdin

0

stdout

1

stderr

2

Merging and Splitting Streams

make –f build_example 2>&1 | tee build.log

File Redirection
This example will make a copy of the file foo.bar

cat < foo.bar > foo.bar.bak

Process Piping
This example will insert line numbers into the foo.bar file

cat foo.bar| nl

Piping vs Redirection
You can do similar things with one or the other. This examples will have the same output.

grep -i example < foo.bar

cat foo.bar | grep -i example

Here Document
You can do some nifty things with here-doc, ‘<<‘. The here-doc command will redirect text into a command or file.

cat << EOF

> Hello World!

> EOF

File Head and Tail

If you’re not first then you’re last. The head command is the beginning of a file and likewise the tail command is the end. The flags -n and -c are important here. To display a given amount of lines you can use -n and to display a given amount of characters in the file you use the -c.

Displaying beginning lines with -n

head -n5 foo.bar

Displaying ending lines with -n

tail -n5 foo.bar

Displaying beginning characters with -c

head -c12 foo.bar

Displaying ending characters with -c

tail -c12 foo.bar

TR

The TR command is pretty useful. Normally, tr is used with two sets of characters, and replaces characters from the first set with characters from the second set.